This proposal requests funds for the purchase of a BIO-Rad MRC-1024 ultraviolet and visible light laser scanning confocal system attached to a Nikon Diaphot inverted light microscope. During the past several years, confocal microscopy has made significant contributions to Biomedical research. This is especially true at the University of Iowa where the BIO-RAD MRC-600 laser scanning confocal system acquired with NIH SIG funding in 1990 has been used by over 120 faculty labs in the 6 years that it has been available. This capability is so valuable to its investigators that in June of 1996, the University of Iowa invested 120,000.00 dollars to upgrade the MRC-600 to a state-of-the-art MRC-1024 system. At this time, it was recognized that this instrument was heavily used, often requiring 10 to 14 days anticipation in scheduling time on it. In addition, numerous confocal investigators were very aware of the need to examine living samples on an inverted microscope with an environmental chamber. Finally, the technology for attaching ultraviolet lasers to confocal systems had recently become both reliable and commercially available. It is for these reasons that this grant application has been prepared. The diversity of new research possibilities is impressive and descriptions of projects that would be undertaken immediately are provided. Apicella will study the biology of pathogenic Neisseria and Haemophilus. Hendrix will examine molecular targeting of a novel breast cancer tumor suppressor gene. Jones will do an analysis of the interactions between invasive salmonella and host cells. Oberly will study how the overexpression of MnSOD leads to inhibition of cancer cell growth. Russo will look at signal transduction pathways controlling CGRP levels in trigeminal neurons. Squier will study the biological basis for oral mucosal drug delivery. Stevens will conduct a characterization of the effect that mutation of COMP has on calcium deposition in chondrocytes. Welsh will look at the localization and transport of ENaC/degenerin Na+ channel subunits. Weisman will examine the molecular basis of organelle division and segregation. The new BIO-RAD system will be conveniently located in room 1 of the Eckstein Medical Research Building as part of the University of Iowa Central Microscopy Research Facility. Administration and maintenance, as well as high-level technical assistance and training, will be provided by experienced personnel within the facility.